Dimensioned Air Photos from Various Flights

Dimensioning (calculating actual sizes of features in the photo) of
some air photos was done to extract information about the sizes of
features. The width and height of the area on the ground captured on
film is a function of the focal length of the camera lens and the
distance to the ground. These photos have been dimesioned applying
the following algorithm:

This assumes the object plane is at nadir from the film plane (camera
is directly overhead, pointing straight down), and that the focal
length is vanishingly small compared to (d). In actuality, none of
the photos are exactly at nadir (near nadir photos were taken by
banking the plane and having the photographer lean farther out of the
window).